The present invention relates to a memory card, and relates particularly to, a memory card which is PCMCIA compatible and has a serial communication interface for serial communication between the card and an external computer or other computer-based system. This invention is suitable for providing a memory card which can connect to a personal computer having a serial communication port, but no PCMCIA compatible interface. The invention further relates to a system and method for enabling serial communication between a PCMCIA compatible memory card and a computer.
Typically, memory cards compatible with PCMCIA (Personal Computer Memory Card International Association) standard are used to install memory in a small form factor for digital computer systems, such as laptops, palm-top, or other computer-based equipment. The memory cards contain a printed circuit board with a 68-pin interface at one end which is insertable through a slot into a PCMCIA compatible interface of a digital computer system. When inserted, memory on the circuit board, typically in the form of FLASH or SRAM memory components, is accessible to the digital computer system. Memory cards under the PCMCIA standard may be Type I, II, or III, and are often called memory PC cards.
Memory on a memory card is conventionally configured at manufacture by a host computer having a PCMCIA compatible slot into which the memory card is inserted. After manufacture it is desirable for users to have the memory of their memory cards updated or otherwise modified to increase their flexibility, such as when a memory card contains information which must be updated to remain current, or contains an outdated version of an application program. Generally, users have had to purchase a new memory card or send the memory card to the manufacturer to obtain the desired updated information or application program. Purchasing a new card, or sending the memory card to the manufacturer each time a memory card update is needed, is both expensive and time consuming.
Although access for updating the memory of a memory card could be enabled through the personal computers usually owned by users, such computers typically lack a PCMCIA compatible interface having a slot to receive a memory card. One solution is for a user to obtain an I/O device having a PCMCIA compatible slot and then coupling the I/O device to a personal computer for communication to a memory card when inserted in the I/O device. This is undesirable since it requires each user to incur the expense of purchase of the I/O device, and connecting the I/O device to a computer can be difficult for the unskilled user.
Accordingly, it is the principal object of the present invention to provide an improved memory card having a serial communication interface which can be easily coupled to an external host computer lacking a PCMCIA compatible interface, thereby enabling the memory of the card to be modifiable by the computer.
It is another object of the present invention to provide an improved system and method for enabling serial communication between a memory card and an external host computer.
It is a further object of the present invention to provide an improved system and method for enabling serial communication between a memory card and an external host computer wherein the memory card has a controller which operates in accordance with commands received from the computer through a serial communication port of the card.
A still further object of the present invention is to provide an improved memory card having a serial communication interface which can function as a typical memory card to enable access to its memory, through a PCMCIA parallel interface on the card, when the card at the parallel interface is inserted into a PCMCIA compatible slot of a digital system.
It is yet another object of the present invention to provide an improved system and method for enabling communication between an external memory card, lacking a serial communication interface port, and an external host computer, lacking a PCMCIA compatible interface, through a memory card having a serial interface to the computer.
Briefly described, the PCMCIA compatible memory card embodying the present invention includes a serial communication interface having a serial I/O (input/output) port, a controller, and a serial I/O transceiver which couples the controller and the serial I/O port to enable the controller to send or receive signals representing data through the serial communication port. Non-volatile memory on the card in one or more memory components is coupled to the controller. A cable connects the serial communication port of the memory card to a serial communication port of an external host computer. The controller operates in accordance with commands received from the host computer through the serial communication port for sending data read from memory of the card to the host computer, writing data to memory of the card received from the host computer, loading a program file (or other data file) into memory of the card received from the host computer, erasing data from the memory of the card, or verifying data in memory on the card. Other commands may be received from the host computer, such as for performing a self-test.
The serial communication port is located at one end of the card, and a PCMCIA parallel interface is located at the other end of the card. The memory card can also connect through a slot of a PCMCIA interface of a digital system, as is typical of PCMCIA compatible memory cards, to enable the digital system to access the memory of the card.
In one embodiment, the computer may communicate through the memory card to an external memory card, which is PCMCIA, CFA (Compact Flash Association), or MCIF (Miniature Card Implementation Forum) compatible, by using a coupler to connect the parallel interface of each card to each other, thereby coupling the controller to the memory of the external memory card and enabling commands received by the controller from the host computer to affect (read/write/erase/program) the memory of the external memory card.
A system also embodies the present invention which includes the memory card, the host computer, and the cable connecting the serial communication port of the host computer to the serial communication port of the card through which information is serially transmitted between the card and the host computer.
The present invention further includes a method for serial data communication between a PCMCIA compatible memory card and an external host computer, which includes: providing a serial communication port on the memory card; connecting the serial communication port of the memory card to a serial communication port of the computer; and communicating information serially between the memory card and the host computer through the connected serial communication port of the memory card and the serial communication port of the host computer.